Zero-Sum
by trufflemores
Summary: 1.23. Eddie doesn't kill himself; the singularity doesn't happen. But it's still hell for Barry.


Eobard pins the twenty-six-year-old Barry to the particle accelerator wall with an iron fist around his throat.

"You're so young," Eobard muses as numb fingers pry uselessly at his wrist. Barry's face is locked in a defiant snarl, chest heaving. Eobard smirks and tightens his grip, just shy of strangulation, prompting Barry to kick, but Eobard holds himself out of reach. Tauntingly, he leans forward and says, "I know how long you can hold your breath, Flash."

Locking in and cutting off his air supply, Eobard continues. "I know how long it takes for you to bleed out. I know how many bones I have to break before you stop fighting." Educationally, he smashes a knee into Barry's abdomen, fracturing a rib. Barry groans, legs twisting as he struggles to stand or double over, unable to comply with either request. " _I know you_."

Another rib-cracking blow. Tears well in Barry's eyes, but the defiance never fades. Eobard likes that; he doesn't know if he could do this to a Barry who evoked pity. It's so much cleaner when the hatred is mutual.

He spent twenty years perfecting the formula Barry was given, countless hours striving to achieve what was thrust on Barry without asking. The knowledge firms his grip and resolve.

Just when Barry's eyes begin to flicker, consciousness scraping his heels against the floor, Eobard lets him go. Barry drops like a stone, gasping for breath and exhaling harshly in pain. A hand stays on the back of his neck warningly. Eobard lets him catch his breath, savoring this moment.

With Older Barrys, he must be careful: he doesn't know how much strength they're hiding.

The brief nature of the encounters doesn't diminish his aching desire to subordinate the great and terrible Flash. It's been a fantasy of his for almost as long as he's known The Flash. To make a king kneel is heady, but to force a _god_ to genuflect is intoxicating. It isn't _like_ mastering the Speed Force; it _is_ mastering the Speed Force.

Eobard feels Barry twist and jerks him warningly to his feet, catching a glimpse of a gun out of the corner of his eye. He Flashes forward and twists the weapon out of reach. Eddie's gun fires harmlessly into the abyss; a knockout punch ensures he doesn't get a second opportunity. Eobard thinks about taking Joe and Iris West out of commission – he finds it unexpectedly difficult to think about doing the same to Caitlin or _Cisco_ – and dismisses the thought when he feels Barry lunge for him.

He feels the Speed Force repulsion and parries the blow, using Barry's momentum to take him off his feet. Barry crashes into the metal floor a hundred yards away, lying motionless on the floor. Eobard stares at him long enough to see his chest rise and fall before returning his attention to the frozen band of non-speedsters.

It's proof that he's unconscious when Barry doesn't rush to their defense. Leaving the gun on the floor, Eobard knocks them out. Live or die, they won't affect his plans. Flashing over, he grabs Barry by the back of the neck, taking off before the bodies hit the floor.

. o .

Eobard presents his prize to GIDEON with unexpected pride.

"GIDEON. We did it," he tells the android, letting Barry drop to the floor and finding his suit compartment.

"Well done," GIDEON remarks neutrally.

Unhooking the tachyonic capture, he turns Barry over and presses it hard against his emblem. Oh, he's hungry, he's _hungry_ , can barely force himself to hold steady, but he must. If he tears Barry open and just _feeds_ on Speed, he'll have his fill faster, but it'll be only once, and then he'll have to find another. He needs Speed. He _needs_ Speed.

He activates the device and Barry's body lurches upward once involuntarily. It's like a powerful magnet, Eobard knows, drawing the Speed Force from him. He presses its twin against his chest with heart-pounding hopefulness. Just when the slowly heating metal seems fit to force his hand into more forceful means of Speed acquisition, he feels a burn in his own chest.

It's more potent than he ever hoped for.

Within seconds, his vision goes gold, his heart beating more heartily than it has in – centuries, it feels like. His breathing settles, slow and deep and easy; the finite tremor in his muscles ceases. Tension evaporates; muscular warmth replaces it. _Run_ , it chants, and Barry writhes a little, coming to and recognizing the parasite on his chest, leaching his life force. _Run_.

He holds his ground, a profound patience sweeping over him. The plan was simple: steal Barry's Speed, kill him, and then return to his present. But he cannot bring himself to unlock the device, even when he is Speed-saturated, head to heel. He's never felt so _alive_.

He feels Barry teeter and doesn't recognize the warning for what it is until the connection breaks. The warmth ceases instantly as a whine builds in his bones, an incessant need for more hammering his chest. He staggers and puts a hand on the wall to center himself, shaking with the force of Barry's speed.

 _I took too much_ , he realizes.

He's known about the critical thresholds for years, scoured it from GIDEON's archives. _If a speedster loses sufficient amounts of Speed, they will no longer exhibit speedster-like characteristics_.

But with Barry – he hadn't thought – Barry had a connection to the _Speed Force_ , he was the only speedster who should never run out –

Yet he did.

Growling, Eobard unlocks the metal clasp on his chest and shuts GIDEON down. Snatching up the cube, the clasp, and his quarry, Eobard spirits them away.

Seconds later, he halts in his hideout, a cramped basement apartment in a nondescript city neighborhood. He prefers his permanent residence, but he knows it'll be the first place the STAR Labs' team looks for him. Dumping Barry carelessly on the floor, he drops the clasp on a side table and opens the cube.

"GIDEON," he asks. The AI's head materializes, at attention. "How do I restore his connection to the Speed Force?"

GIDEON replies, "A jumpstart could prove effective."

Eobard thinks about surrendering some of his own Speed, his newly acquired, stolen Speed, and growls. "Alternatives."

"Artificial replication," GIDEON answers serenely. "Duplication of preliminary conditions."

Eobard frowns. "Alternatives."

"There are no further alternatives."

Expressing hardening, Eobard's grip tightens on the cube. " _Alternatives_."

"There are no further alternatives."

He shuts the cube with a quick snap. He's not giving back the Speed – if he does, it may not work, and then he'll be worse off than before – but he can't use artificial Speed to recreate the Speed Force, and he can't risk a second particle accelerator explosion. Thinking back to Farooq and his ability to steal The Flash's speed (God he should have figured out how _then_ ), he howls in unexpected pain when a metal shard punches through his calf.

Twisting, he kicks Barry away from him, yanking the shard out and throwing it aside. He'd be impressed if he wasn't furious that Barry managed to break it off of the tachyonic capture without him noticing. As it stands, he lifts Barry up by his throat, clean off the floor, and snaps, "Try that again and I'll break every bone in your body."

Twisting weakly in furious resistance, Barry tries to Flash out of his grip, eyes glowing almost red with lightning, and Eobard aches to take, take, _take_ , but he just crushes Barry's throat in his grasp instead, forcing compliance.

He holds on long, too long, because he told Barry he knew how long The Flash could hold his breath and wasn't lying, and he sees the panic finally spread across Barry's expression seconds before his eyes roll back into his head. Eobard drops him and Barry hits the floor.

Even with his agitation creeping back in, _more more more_ , he feels powerful, healthy. Whole. The wound on his leg is an ache, a subtle forgettable pulse rather than a delirious ache.

He forces himself to calm – _don't use it all don't use it you won't get it back_ – and sits on the edge of the couch. Inhales. Exhales.

He doesn't know if Barry's actually breathing, but sitting with meditative stillness, he doesn't care. Let him die, he thinks, suddenly sure. If that is this Barry's fate, then he won't be the first, and inconveniencing as it would be to have to fight for another vulnerable Barry, one who hadn't mastered his Speed and perfected his armor, Eobard could do it. Eyes closed, he pictures it, the powerful Barry, all that untapped potential still present because Barry couldn't possibly use it all, and he feels a twist of jealousy in his stomach that hurts, and then he sees himself striking down The Flash, in his prime.

He _wants_ it.

Resolved, he opens his eyes, and reaches over to unhook the clasp from Barry's chest. He holds onto it for a moment, leaving it there, heartbeat loud in his ears. _I could kill you,_ he reflects, a familiar prophecy, as he holds onto the still-warm metal. _It wouldn't even hurt, like this_.

He has killed other Barrys, young and powerful, infirm and extraordinary. He's quick, decisive, ruthless. It wouldn't even hurt, he thinks, almost dizzied with the thought, because he has spent fifteen _years_ protecting this Barry, helping this Barry, making sure this Barry survived. He spent sleepless nights worrying about this Barry, killing people _for this Barry_ , and even with victory just under his fingertips, he doesn't take it.

He can't.

Standing, he finds his Speed-resistant cuffs and pins Barry to the coffee table, resolving to deal with it once he wakes up. All Barry has to do is irritate him and he can let his annoyance make the final call for him. Given that frustrating behavior is one of Barry's specialties, he has no doubt that Barry will comply. It relaxes him, enabling him to venture out of sight, raiding the kitchen in a real-time blink-of-an-eye.

Still the Reverse hungers, insisting, needing, whispering to him. _Take_.

Eobard's lip curls, his appetite vanishing. _I can't_ , he snaps, leaning a hand on a chair.

 _Take_ , the anti-Speed Force snarls. _Take, take, take._

He stalks over to the couch, smashes the tachyonic device onto his chest without hope, and jerks, startled, when he feels it start to warm. With tangible delight, he reaches up with a shaking hand to twist it, turning it off, afraid to take too much too soon but thrilled that there is still _more_.

 _Take_ , Reverse clamors, but Eobard shoves it down.

It's easy to be patient like this, he thinks, as he crouches in front of a reviving Barry with glowing golden eyes.

" _Oh, you're going to regret not letting me kill you,_ " he says with a wicked smile.

Barry flinches. Eobard's pride _purrs_.

. o .

It can't last. Of course it can't. But ninety-two hours is still far more than Eobard ever hoped for.

Four _days_.

He thinks about killing Barry, as a parting gift – Barry's hanging on by a thread as it is; _humans can survive for up to three weeks without food_ – but he lets him live. Because he knows this Barry won't come after him.

He flinches just looking at Eobard. The metal clasp on his emblem is like a brand, designed to withstand the Speed Force, resisting his feeble attempts to remove it. Eobard pries it off effortlessly, compresses it, pockets it. He might need it someday.

He grins. He hopes to.

Even the Reverse seems satiated, for once not tugging at him, insisting that he keep his quarry, and he knows it's time to go. "It's been fun, Flash," he tells Barry, leaving him chained to the floor.

He vanishes seconds before the door bursts open, admitting the harried remnants of the STAR Labs' team.

Let them have their Barry, he thinks as he races across the city, merging with the Speed Force for the first time in years. If he gets to have his world, they can have theirs.

. o .

Skating to a halt in the future, Eobard takes a deep breath of the night air, dizzy with relief. He's home. He's _home_. The surplus lightning is already fading because time travel takes too much, but he doesn't care because he never has to go back, he can stay here, he's home, he's home, _he's home_.

That's when he feels it: there's someone watching him.

Exhaling, he tries to savor his final seconds – clear night air, damp grass underfoot, the call of an empty field beckoning him – before he turns on his heel with submissive slowness.

The Flash angles towards him, a saunter that could be lethal betraying his calm. He's got the red suit on, and Eobard relaxes. To be fair, he thinks, with a shiver of remembrance, if it was blue, he wouldn't know – none of his time remnants survived those encounters – but he's grateful for the smallest mercy of the multiverse.

Flash speaks first, in a tone deeper, more refined, and so much heavier than his younger counterpart's: "I was beginning to worry."

Eobard takes a slight step back before steeling his stance. Flash draws up level to him, staring him down. Reflexively testing the waters, Eobard jerks to one side, a false retreat, and Flash mirrors the movement exactly, pursuing. There's a warning golden glow in his eyes. _Don't run._

Without a word, Eobard holds his ground.

Flash regards him for a long time, unblinking, unflinching, and Eobard starts to ache for something to respond to. Bracing himself to run, regardless of its futility, he holds his breath when Flash reaches out. A hand settles on his shoulder and for half a second Eobard cannot react, frozen in place, and in that half-second Flash _does_. Eobard would know the lightning anywhere, and an ache between his teeth and eyes that he did not know what building dies.

Noiselessly strangling on it, he can't move, can't breathe, consumed by the Speed Force, by the sheer overwhelming _warmth_ of it, and then Flash lets go and it still crackles around him, like a fire, holding on.

The warmth in Flash's eyes is a little dimmer, revealing Barry's, and Eobard can't speak.

Barry steps back, still suited up, still more powerful than Eobard could ever hope to be, putting a little distance between them. Still in comfortable speaking distance, he says quietly, "This isn't a zero-sum game."

Eobard stares at him, at all he represents, all of that _power_ , power unused, he could rule the multiverse, but instead here he is. In one place and time, staggering on under a weight too heavy for human shoulders. _The great and terrible Flash_.

And it occurs to Eobard that it doesn't matter how old or young Barry is: that rule will always apply.

When Barry takes off he doesn't follow, watching the red streak vanish.

Eobard closes his eyes, a strange mix of defeated and relieved.

Sometimes he doesn't win against The Flash, but maybe he wasn't playing the same game.

. o .

 _Coda._

It happens in Speed-time; Barry knows because no one else turns to look at the speedster in the corner of the Cortex.

The Future Flash saunters closer.

Barry doesn't move, still lethargic despite the IV and protein bars he managed to keep down. It seems like a dream, the presence of a temporal doppelganger, here-of-all-places. He asks, "What are you doing here?"

The Future Flash admits, "Helping, I hope." Then, eyes hard with unexpected fierceness, he sits on the side of the bed and adds, "I won't let him come back."

Barry's shoulders lower in relief. "Thank you," he says.

The Future Flash nods, stands. "Any time," he replies simply, and vanishes, a blur of red light that makes Cisco jump and Caitlin flinch, what-was-that?

"S'okay," Barry tells them, eyelids fluttering shut. He's tired, drained in more ways than one, but he feels safer knowing he isn't alone.

And maybe he feels safer knowing Eobard isn't alone, either.

 _I won't let him come back._

And the Future Flash keeps his word.


End file.
